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What's to come when Warren Buffett's holding company reports its second-quarter earnings, and a look back at developments during the quarter.

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One of Wall Street's most closely watched companies, Berkshire Hathaway (NYSE:BRK.A)(NYSE:BRK.B), is set to report its second-quarter earnings after the market closes on Aug. 4.

With many billion-dollar brands under the conglomerate's umbrella, there are many moving pieces that affect its quarterly earnings. Here are a few of Berkshire's most important businesses and some developments from the quarter.

Berkshire's biggest business

The manufacturing, service, and retailing (MSR) businesses have quietly grown to become the largest source of Berkshire's profits, after Precision Castparts and Duracell were folded into the segment in early 2016.

This quarter is an important dividing line in its reporting, as it's the first quarter in which Berkshire Hathaway will lap a prior-year result that includes the full impact of Precision Castparts and Duracell, making its second-quarter results a better measuring stick than its performance in prior periods.

The "industrial" businesses of this group are the needle movers. The industrials group includes some familiar names, such as Precision Castparts, Lubrizol, IMC, CTB International, and Marmon, to name a few, which generate roughly 20% of total MSR revenue but more than half of the total segment's pre-tax earnings.

Image source: Matt Koppenheffer.

The risk business

Insurance is a fickle industry, as performance is driven by industry cycles as well as seasonality. Reported earnings can also be affected by simple timing. For example, BH Reinsurance's first quarter was negatively affected by $270 million of insurance losses that stemmed from events occurring in prior periods. In short, a single quarter's results are a very bad basis on which to judge an insurer.

Further complicating quarterly reporting is that Geico is stepping on the growth pedal and thus spending more to bring in new business as competitors exit. Whereas other businesses grow by investing in property and equipment, which doesn't affect the income statement, insurers like Geico grow by spending on labor and marketing, which flow through the income statement. When it comes to growth, insurers have to accept short-term pain for long-term gain.

Buffett has been outspoken about Geico's ability to gain share by competing aggressively for new business, and it appears that the investment is paying off. Berkshire's first-quarter filing with the SEC stated that Geico's "voluntary auto new business sales in the first quarter of 2017 increased 30.2% compared to the first quarter of 2016."

We'll see what picture the insurance businesses collectively paint this quarter, but what's most important is that, over the long haul, Berkshire can maintain its status as one of the most profitable insurers on an underwriting basis. The key metric: A combined ratio under 100 over a period spanning years, not a single calendar quarter. Given Buffett's bearishness on the reinsurance industry, premium growth or decline in that line of business is also worthy of careful observation.

Earnings in energy

The regulated utility business is perhaps the least interesting of the Berkshire Hathaway complex, because surprises are few and far between. Regulated utilities operate in monopolistic local markets in which regulators essentially guarantee a satisfactory return based on the amount of capital employed in the business.

The only "surprise" here is that Berkshire Hathaway is in the midst of a $9 billion deal to purchase Oncor Electric Delivery Co., the sixth largest energy distribution utility in the United States. Activist investor Elliot Management outlined a competing bid for the utility company, but it has only until Aug. 21 to find financing partners to back its proposal.

If nothing else, this transaction provides a real-time test of the Berkshire Hathaway brand in the eyes of state regulators, who have historically welcomed Berkshire as an acquirer of public utility assets. Notably, Texas regulators have already denied proposals from NextEra Energy Inc. and Hunt Consolidated to acquire Oncor, and Oncor has said Berkshire's offer is the best so far. Time will tell. In any event, expect nothing more than steady operating results for Berkshire's utilities segment.

Recovery on the rails

The railroad business is broadly performing better than in 2016, helped by an increase in total carloads in almost every week of 2017 compared with the year-ago period, according to data from the American Association of Railroads. Coal shipments are the most improved, though they remain well below levels seen in 2014 and 2015.

Railroads are really a commodity business, in the sense that prices for energy commodities have an outsize impact on railroads' bottom lines. That said, we can get a general feel for BNSF's results by looking at the results of railroads that have already reported for the second quarter.

BSNF's Omaha-based rival, Union Pacific, reported that its second-quarter earnings jumped 19%, helped by an increase in industrial and coal shipments. CSX also saw its coal-related shipments increase, driving earnings growth in the second quarter, though its management sees coal shipments gradually decreasing over time as utilities move toward natural gas.

The bottom line: The industry's profits are improving, but there's still a very long way to go to get back to the profits of 2014 and 2015.

The investment portfolio

Berkshire Hathaway made a few headline deals during the quarter, investing in Home Capital Group, a Canadian bank, and purchasing nearly 10% of Store Capital, a U.S.-based retail REIT. Berkshire was also rumored to be in discussions to work with Liberty Media Corp. on a $10 billion to $20 billion investment in Sprint. The telecom deal seems to have fallen apart.

Berkshire Hathaway made a few other moves in its public securities portfolio. It announced its intention to swap its Bank of Americawarrants for common stock after the Charlotte, N.C.-based bank raised its dividend that made the common more attractive. Berkshire reportedly sold about one-third of Berkshire's stake in IBM in the first and second quarters of the year. It also sold a small amount of Wells Fargo shares so as to keep its holdings below the 10% threshold.

A major owner of American Express, Berkshire quietly filed for approval to own as much as 25% of the closed-loop card company in May. Berkshire's stake in AmEx has slowly increased as the company deploys excess capital to repurchase stock, making Berkshire's shares a proportionately greater part of the AmEx pie.

The piggy bank

Berkshire's bank account is arguably its single-largest "business." The company ended the first quarter with roughly $96 billion in cash, which is piling up at a rate of about $20 billion per year.

Buffett addressed its excess cash at the annual meeting, suggesting that the growing cash pile makes it more likely that Berkshire may have to explore ways to return cash to shareholders. "There's no way I can come back here three years from now and tell you that we hold $150 billion or so in cash or more and we think we're doing something brilliant by doing it," he said at the annual meeting.

Berkshire's all-cash offer for Oncor would put a small and temporary dent in a growing pile of excess cash on the company's balance sheet. But the clock is ticking. At some point, Berkshire may have to do the once unthinkable by instituting a regular dividend to return cash to investors.